Unnamed (Russell Island)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Pb; W; Zn
Ore minerals galena; native gold; pyrite; pyrrhotite; scheelite; sphalerite
Gangue minerals ankerite; calcite; dolomite; quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale MF
Quadrangle map, 1:63,360-scale D-3
Latitude 58.9414
Longitude -136.8131
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site is a small bight on the northeast tip of Russell Island (Kimball and others (1978, figs. C45 and C55). The location is accurate within 0.10 mile. Another vein cropped out 1000 feet west-northwest of located vein. The locality is number 29 of Cobb (1972).

Geologic setting

Geologic description

Russell Island is underlain mainly by granodiorite of Cretaceous age (Brew and others, 1978). On the northeastern part of the island, quartz veins as much as about 0.5 feet wide occur in ankeritic (iron-stained) zones as much as 4 feet thick that cut the granodiorite. The main vein occurrence has an estimated length of 280 feet on the island. It strikes N. 15 degrees E. and is nearly vertical. It extends across the small peninsula between shorelines of Glacier Bay at the northeast tip of Russell Island (Kimball and others, 1978, fig. C55). The quartz veins within the ankerite shear zone contain ankerite, pyrite, pyrrhotite, sericite, dolomite, calcite, and traces of scheelite. The pyrite contains native gold particles visible microscopically. Two additional, narrow iron-stained vein zones are 1,000 feet west-northwest of the main vein zone. The Russell Island occurrences appear to represent the approximate northeast limit of the Reid Inlet gold area.
Channel samples of selected veins contained more than 5 ounces per ton gold, and a weighted sample reduced to a 4-foot mining width contained 0.35 ounce per ton gold.
Geologic map unit (-136.814975704373, 58.9410005968491)
Mineral deposit model Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization Late Cretaceous or younger.
Alteration of deposit Granodiorite has been altered; alteration products include chlorite, sericite, introduced quartz, and probably ankerite or dolomite.

Production and reserves

Workings or exploration
Surface exposures only. Channel samples of selected quartz veins contain as much as 5.81 ounces per ton gold, 2.64 ounces per ton silver, 890 ppm lead, 550 ppm zinc, and less than 50 ppm tungsten. (Five of fifteen samples from the veins show a trace of tungsten as does one of two samples from the vein occurrence 1000 feet to the west-northwest.) Weighted values for 4-foot mining widths range from 0.02 to 0.35 ounce per ton gold and from 0.02 to 0.17 ounce per ton silver (Kimball and others, 1978, p. C238-241).
The occurrence may have been discovered by the U.S. Geological Survey in 1966; MacKevett and others (1966) reported a narrow quartz vein at the site contained 0.844 ounces of gold per ton.
Indication of production None

Additional comments

Area warrants further exploration; it is within Glacier Bay National Park and Preserve.